A combine harvester includes a header, a pickup reel, a cutter, a threshing drum, sieves, a collection tank, and conveyors, such as rotating belts and spinning augers and fans. The header gathers the crop, and the pickup reel pushes the crop down toward the cutter, which cuts the crop at the base near ground level. A conveyor picks up the cuttings from the cutter, and conveys the cuttings to the threshing drum, which rotates and threshes the cuttings separating the grains from the chaff to form threshings, namely, the chaff and the separated grains. A conveyance conveys the threshings along the thresher from an upstream location of thresher to a downstream location of thresher as the thresher rotates and the grains fall through sieves into a collection tank inside the combine harvester, which is periodically emptied, such as into tractors that drive alongside, while a conveyor takes up and conveys the chaff to the ejection spout for ejection onto the field. Some combine harvesters have a rotating spreader mechanism that throws the chaff over a wide area, while others have bailers that bail the chaff for later use, such as for animal bedding.
Typically, a number of threshing bars are secured to the outer surface of the threshing drum. As the threshing drum rotates, the threshing bars thresh the crop material between the outer surface of the threshing drum and the concave.
Threshing bars inherently wear over time, which inherently diminishes the ability of the threshing bars to efficiently thresh the crop material compared to unworn threshing bars. Threshing bars must, therefore, be periodically replaced when worn.
Some threshing bars incorporate raised spikes or cutting blades useful for threshing crops such as rice and other crops having inherently tough straw. These spikes and cutting blades inherently dull and wear over time, typically at a rate that is faster than the remaining threshing bar threshing surfaces due to their exposure. As a result, threshing bars having raised spikes and cutting blades must be replaced sooner compared to threshing bars having no such spikes or cutting blades. Accordingly, there is a need in the art for threshing bars having spikes or cutting blades configured to resist wear from prolonged use for reducing the frequency of threshing bar replacement until the remaining threshing surfaces become sufficiently worn to require bar replacement.